Poop in a Bucket – Thoughts on our Composting Head

While we probably have received the most inquiries about where our mast is, questions about our composting toilet are definitely number two. Hehe.

Replacing our traditional marine flush toilet and holding tank with a composting toilet was the first big boat project we did after purchasing our Tartan 37. We have been living with our composting toilet for a while now and have gotten a feel for pooping in a bucket so to speak, and would like to share with those who are curious about making the switch.

As with most decisions, we approached this one fairly methodically, however in full disclosure, there was one pretty major factor that influenced our decision:

We already owned the composting toilet.

We actually purchased the composting toilet (before buying our Tartan 37) to put into another boat we had under contract, because that boat had no toilet whatsoever, and the composting toilet was going to be the easiest/quickest to install. When that boat purchase fell apart we were left without a boat — but we had a brand new composting toilet!

Back to our decision making process…

One thing we loved about our Tartan was that she smelled amazingly good. No diesel odor, no mold or mildew, and the distinct odor of human waste — inescapable on many boats — was nonexistent. Much of this was due to the previous owners never using her as a full-time liveaboard. She was kept at a dock, sailed mostly on weekends and the occasional multi-week summer trip — all in FRESH WATER. To top it all off, she was well-loved by her previous owners, who kept her in immaculate condition.

And we were about to change all of that completely. We planned to liveaboard, and saltwater was in our future.

At the top of that list was replacing our marine head and holding tank.

Why We Replaced our Marine Head with a Composting Toilet

We quickly realized that the only reason the head didn’t smell was because it wasn’t really being used. Once we started using it, that changed quickly. And the smell permeated everything. Even when you weren’t physically using the toilet at that very moment, the smell was there. It was disheartening.

During one rough passage, we went down below to see water backing up into the bathroom sink and the toilet bowl. My first thought was that water was coming up the thru-hull and filling them both up, since we were beating into some heavy winds and heeling over pretty good. I quickly remembered that we had a Y-valve under the sink that allowed fresh water to be pumped into the toilet from the sink, or raw water from the thru-hull; I figured it had been left in the wrong position allowing water from the lake to enter the boat through the sink and siphon down into the toilet. So I closed it, and went back up on deck.

Still being rather new to the boat, I thought I had solved the problem. Ten minutes later I went below to check up on the situation…

AND IT WAS SO MUCH WORSE.

Now there was much more water in the toilet bowl and the sink than before and it was brownish in color and it was spilling out into the head pan with each wave we crashed into! All the reading I had done about disasters at sea and how to survive them did not prepare me for this one…this was a different kind of disaster I hadn’t imagined.

As many of you know, the joke was on us — our joker valve was bad — but it was exactly at that moment we knew we never wanted to deal with that situation again. We pulled out the holding tank as soon as we got back to the dock.

Composting Toilets vs. Marine Head & Holding Tank

There are a number of benefits to replacing our marine head with a composting toilet, in addition to simply avoiding sewer water splashing about the boat:

PROS

We can go longer between ‘removing’ our waste. We used to have a 12-gallon holding tank in the v-berth. This is pathetically small. The two of us together generate just over 1 gallon of liquid per day, then adding solids and the water required to flush, means we could go maybe 5 days between pump-outs — if we were lucky!?! We can go a good week and a half before needing to empty the composter — and this is using the smaller 3-gallon C-Head which we had to go with because of the smaller size of our bathroom/head.

We reduced weight onboard. 12 gallons of liquid/solids is heavy! We didn’t like having all that weight at the pointy end of our boat.

We opened up more storage space for other things. We gained a bunch of storage room under the v-berth, and completely opened up the previously unusable hanging closet aft of that once we removed all the massive hoses and plumbing that ran through it connecting the head to the holding tank.

The smell literally disappeared. The only smells we have now are when we open the lid to the toilet, and to be honest it’s mostly the liquids that smell. (And a spritz of vinegar into the bowl helps with this.) The solids portion of the toilet is quite tolerable.

We get to choose when to deal with emptying the waste. We don’t have to be back at a dock every few days to get a pump-out.

We save money not paying for pump-outs.

We save the precious fresh water that was once used to flush.

We closed off an unnecessary thru-hull.

There are almost no moving parts, almost nothing that could break, and next to NO maintenance — just cleaning.

If anything does break, every single component can be easily sourced and fabricated anywhere in the world. It’s literally a bucket with some PVC pipe inside.

Cons

There is really only one negative. It shows itself a few different ways, and can be a big turn off for some: You will be physically more intimate with your solid waste. With a traditional marine head, you don’t really have to deal with it until something breaks, but then you’re really up close and personal with it. You can pump a lever to flush it out of sight and into the holding tank. You then pay someone to pump it out of your boat and haul it away for you. Essentially once you’ve done your business you may never need to see it again. Unless of course, UNTIL SOMETHING BREAKS. And it will, at the worst time, in the worst place, and it won’t be pretty. With the composter, you’ll be dealing with it yourself on regular basis, but with much less drama. After you do your business you’ll need to cover it with a composting medium, then once the container is full you’ll empty it yourself. It doesn’t get flushed away, you won’t be paying someone to remove it. But — and it’s a huge BUT — doing so makes all the difference. Solid waste in the composter is so much more tolerable than the soupy sludge found in clogged marine toilets and holding tanks. So if you can get over the initial ick factor, it’s so totally worth it.

Thoughts on the C-Head

They are all fundamentally the same device, and function in a very similar way: they each separate solids from liquids, churn up the solids to keep them covered and empty when needed.

Each may perform these tasks in a slightly different manner, but choosing between the available options is likely to be based more on size and price than any available specific features.

We went with the C-Head and are quite happy with our decision. Besides being the smallest option (which was necessary to get it to fit next to the contour of the hull in our head) it was also the cheapest which was a nice bonus. And to top it all off, it was built by a sailor specifically for sailors. This becomes obvious in a few key areas we’ll point out below. The Nature’s Head seems to be marketed more towards off-grid living as a replacement for a normal household toilet, and the Airhead seems a little more RV-oriented.

The C-Head is dead simple, and aside from the faux teak which blends in nicely with the rest of our interior, the remaining parts and pieces could be sourced anywhere in the world, if there was ever a repair needed. The agitator is made out of common PVC pipe, the liquids container is a milk jug that can be replaced with any other milk jug at any time. And the solids container is literally a 3- or 5-gallon bucket. Minimalism and simplicity are awesome.

The other major advantage of the C-Head for us was the simplicity of cleaning and emptying. Remember this is the one big negative for composting heads — you have to deal with your waste yourself — so seeing as it’s just a 5-gallon bucket, it is incredibly easy to dispose of the waste, whether it’s over the side while offshore, or into a garbage bag when appropriate, hosing it down and bleaching it if need-be or dragging it through the saltwater, all makes quick work of the job when you want to get it cleaned up.

In Summary

Would we make the same decisions again if in a similar situation? Yes, absolutely. We’re very happy with the composting toilet, and happy with our choice of a C-Head.

If we could design our perfect waste-disposal system, in our perfect boat?

It would be this: A composting toilet for in-shore business in one hull, and a traditional marine head (no holding tank) for going straight into sea while offshore in the other hull. Yup you read that right — two hulls. We can dream. 😉

Our head and tank haven’t caused any drama for us, so a C-head has been a low priority. That said, we’d love to do for out Tartan what you’ve done, and maybe dedicate the space recovered to a water maker of some sort, using the thru-hull for water intake.

Sounds like a great idea! We used the extra space where the holding tank was for spares. If we decided to get a watermaker we agreed we’d pull the port water tank and put it there. Which would still give pretty easy access to that through-hull, but would also open up a bunch of extra can-food and tool storage.

I am also considering a liveaboard in the next year or two, and I ‘think” I am sold on the Tartan 37 too. It seems to have good sailing traits, and quite seaworthy, as well as a great vessel that keeps much of it’s value if taken cared for and modernized when needed! It’s seems big enough for two, although I plan on being solo. What about being solo? Could you imagine swinging that? MY dream, is to navigate the Caribbean first, but toward Aruba, then maybe thru the Panama Canal to Costa Rica? THis is a good enough vessel for this? I think YES! I like the idea of the composting toilet. THanks so much for sharing your experiences!! Nick

Sounds like an awesome plan. With the right upgrades, any boat can be set up for solo-sailing, just depends on how many electronic gadgets you want to rely on. That said I think the T37 would be easily single handed. The only area that’d be tough for us to solo is anchoring, but that was a conscious choice to go with an electric windlass. Swap out our manual for an electric and you’d be set. Our main halyard runs to the cockpit, the jib sheets are in reach while at the wheel, the mainsheet is on the coachhouse but it’s easily run back to the helm while under sail, or with the autopilot, it takes just a moment to make an adjustment. The boat’s not so big that you can’t push it around by hand in most wind conditions while at the dock, and it is sized perfectly for two, one would be fabulous!

Hey, Kirk – Thanks for the breakdown on the composting toilet. A few questions come to mind: What is the composting medium that you’re using? Will you be able to find it outside the U.S.? When you’re at a dock, where do you empty the liquid waste container (overboard?)? Lastly, (probably a novice question) Does the sink go to another holding tank?

We started using aspen shavings, and have purchased coconut coir to try that out when the aspen shavings run out. We have enough for a number of months right now. I’m sure we’ll be able to find something no matter where we go. When we’re at the dock we rarely use the head, and prefer to use the shore facilities. The sink drains directly into the water, no holding tank. We know a number of cruisers, who even with a holding tank, prefer to deposit liquids into a separate container, and then actually dump that through their sinks or overboard.

We had a C Head in our last boat and were very pleased with it. So much so that we now have a Nature’s Head on our current boat. We experimented with media as well and have ended up using the coconut coir. If you are not actively cruising and the head will be left for periods of time, we found that it is a good idea to pre-bake the coir in an oven prior to stocking it on the boat. That will kill off any insect eggs that may be hiding in the coir. Twice prior to starting this practice we returned to a boat full of small friends that we had to clean up, so I researched it a bit and discovered the baking trick. Even so, we have found that the coir is our go to media now and will remain so, for what it’s worth. Good luck out there.

Good tip! Thank you for sharing. We just ran out of aspen shavings and are trying the coir now. So far the coir does a better job of pest control, but we actually miss the smell of the aspen shavings it was like walking into a high-end closet, or a crisp mountain forest. The coconut coir doesn’t necessarily smell bad, but is definitely more “earthy”.